Use of Nifuratel to treat infections caused by Clostridium species

Description

[0001] The present invention relates to the use of nifuratel, or a physiologically acceptable salt thereof, to treat infections caused by Clostridium species. The invention is further directed to the use of nifuratel to treat Clostridium difficile infection (CDI) and in particular Clostridium difficile associated diarrhoea (CDAD).

BACKGROUND OF THE INVENTION

[0002] Clostridium difficile, a Gram-positive, spore forming, anaerobic bacillus, is a leading cause of antibiotic-associated diarrhoea in hospitals and long-term care facilities. Clostridium difficile infection (CDI) can arise when patients receive broad spectrum antibiotics (clindamycin being considered as the main responsible) that alter the ecological balance of the normal intestinal flora, allowing C. difficile proliferation and toxin production. Symptoms of CDI may vary from mild diarrhoea to life-threatening pseudomembranous colitis, fulminant colitis, toxic megacolon and death. These symptoms are mainly caused by the cytotoxic effects of toxin A and toxin B produced by C. difficile. Diagnosis of CDAD is made upon both clinical signs and symptoms and upon detection of toxin A and B in the stool using an enzyme-linked immunosorbent assay (Parkes G.C. et al. Lancet Infect Dis 2009, 9:237-44; Cohen S.H. et al. Infect control Hosp Epidemiol 2010, 31(5):431-455).

[0003] Little is known about the extent of Clostridium difficile infection in Europe. Since 2003, increasing rates of C. difficile infections have been reported in Canada and USA, with a larger than previously reported proportion of severe and recurrent cases occurring in those countries.

[0004] The raised incidence and virulence of such infection have been partially explained by the indiscriminate use of antibiotics belonging to fluoroquinolone class, which caused the selection and spread of fluoroquinolone-resistant strains belonging to the PCR ribotype 027. Ribotype 027 was first reported in England in 2005, subsequently epidemics of this ribotype have been reported in many other European hospitals (Bauer MP et al. Lancet 2011, 377:63-73).

[0005] In the art, treatment of CDI is mainly limited to oral metronidazole or vancomycin both given for 7-14 days. Both treatments are highly effective against C. difficile and are equivalent in terms of overall response, although vancomycin therapy has been associated with a shorter mean duration of symptoms. Symptomatic recurrences are common following treatment with metronidazole or vancomycin. Many health authorities now recommend metronidazole as the first-line treatment agent because it is considerably less expensive than vancomycin, and in order to reduce the selective pressure for vancomycin- resistant enterococci (VRE) (Cohen S.H. et al. Infect control Hosp Epidemiol 2010, 31:431-455; Freeman J et al. JAC 2005, 56:717-725).

[0006] The severity of the consequences related to the current therapeutic options asks for an adequate treatment of CDI and CDAD. A few molecules are currently under development for the treatment of CDI, but they are in a very early stage. (Johnson A. P. Expert Opin Ther Patents 2010, 20:1389-1399). Thus, there is still an unsatisfied medical need in terms of efficacy and prevention of relapses.

[0007] Nifuratel is a nitrofurane derivative effective in the treatment of vaginal infections caused by protozoa (Trichomonas vaginalis) and by bacteria, such as Gardnerella vaginalis (Mendling W. et al. Arzneim Forsch Drug Res 2002, 52(1):8-13) or Atopobium vaginae (WO2010/121980).

[0008] It has now been surprisingly found that nifuratel, besides being active on vaginal pathogens, is also active against different Clostridium species.

DESCRIPTION OF THE INVENTION

[0009] The object of the present invention is represented by the use of nifuratel, or a physiologically acceptable salt thereof, for use in the treatment of any infection caused by Clostridium species, such as Clostridium difficile, Clostridium butyricum and Clostridium beijerinckii. More particularly, it is represented by the use of nifuratel, or a physiologically acceptable salt thereof, for treating Clostridium difficile infection (CDI) and, in particular, Clostridium difficile associated diarrhoea (CDAD).

[0010] Solid, semi-solid or liquid preparations of nifuratel or of a physiologically acceptable salt thereof, in the form of oral tablets, film-coated tablets, capsules, dragées or syrup, with a content in nifuratel from 10 to 1000 mg per single dose, more preferably from 50 to 800 mg per single dose, most preferably from 100 to 600 mg per single dose, are suitable to treat infections by Clostridium spp.; such preparations may be administered to infected patients according to conventional techniques; according to a preferred embodiment, they are administered on a regular basis, preferably three times daily.

[0011] Pharmaceutical compositions may be prepared according to conventional techniques, may contain pharmaceutically acceptable excipients, adjuvants and/or carriers, and may also contain, in combination, one or more active principles with complementary or, in any case, useful activity.

[0012] The active agents which may be used in combination with nifuratel of the present invention include, but are not limited to, antibiotics, antidiarrheal agents and probiotics; such active ingredients may be administered together with nifuratel (i.e. they may be for instance contained in the same composition as nifuratel) or they may be administered separately from or in temporal proximity with nifuratel.

[0013] Examples of antibiotics include metronidazole, vancomycin, bacitracine, rifaximine, aminoglycosides such as neomycin, gentamycin, amikacin, kanamycin and salts thereof. Examples of the antidiarrheal agents include: bismuth subsalycilate, aluminium silicate, kaolin, activated charcoal, loperamide, attapulgite, zinc. Examples of probiotics include species of the genus Lactobacillus, Bacillus clausii and Saccharomyces bouillardii.

[0014] Examples of the compositions prepared according to the present invention include: tablets, film-coated tablets, capsules, dragées or syrup suitable for oral administration.

[0015] The pharmaceutical compositions and the uses of the present invention will now be more fully described by the following examples. It should, however, be noted that such examples are given by way of illustration and not of limitation.

EXAMPLE 1

[0016] An in vitro study was performed to investigate the susceptibility of 3 strains of Clostridium difficile (1 reference strain, ATCC 17858 and 2 clinical isolates), 1 reference strain of C. butyricum (ATCC 17791) and 2 reference strains of C. beijerinckii (ATCC 8260 and ATCC 17795) to nifuratel, compared to metronidazole and vancomycin. MICs were determined by the broth dilution method in Brucella broth (BB) supplemented with Hemin (5µg/mL), vitamin K1 (1µg/mL), laked horse blood (5%) and Oxidase (1:25 v/v), according to CLSI M11-A7. Nifuratel, vancomycin, metronidazole (previously dissolved in dimethyl sulfoxide) were added to the medium. The ranges of the concentrations tested were 0.125-128 µg/ml for all compounds.

[0017] The in vitro activity of nifuratel against the tested strains of Clostridium difficile (MIC range: ≤ 0.125 - 0.25 µg/ml) was comparable or better than metronidazole (MIC range: 0.06 - 0.25 µg/ml) and vancomycin (MIC range: 0.25 - 0.5jug/ml).

[0018] A quite good activity was observed also with C. butyricum and C. beijerinckii.

Table 1: Comparison of MICs for different strains of Clostridium spp.

Strain	Nifuratel µg/ml	Metronidazole µg/ml	Vancomycin µg/ml
C. difficile ATCC 17858	0.25	0.25	0.5
C. difficile	0.25	0.06	0.25
C. difficile	<0.125	0.125	0.25
C. butyricum ATCC 17791	1	1	1
C. beijerinckii ATCC 8260	0.5	0.125	0.5
C. beijerinckii ATCC 17795	4	0.5	0.5

EXAMPLE 2

[0019] Oral tablets are produced with the following quali-quantitative formula:

Ingredients	Quantity (mg /tablet)
1. Nifuratel	200.00
2. Maize starch	65.00
3. Talc	30.00
4. Polyethylene glycol 6000	14.00
5. Magnesium stearate	2.00

[0020] The process consists on the preparation (protecting from light) of binder solution with water and polyethylene glycol heat at 45°C under continuous stirring; then granulate in a Glatt fluid bed basket by blending nifuratel and starch until the mass is homogeneous, before spraying with the binder solution, then dry at inlet air temperature of 60°C; then add talc and magnesium stearate. Tabletting is done in a rotary tabletting machine with an appropriate punch.

[0021] The obtained tablet has a smooth surface with a yellow colour.

EXAMPLE 3

[0022] A syrup having the following composition wt./wt.% is prepared:

Ingredients	Quantity (g /100 ml syrup)
1. Nifuratel	4.0
2. Polysorbate 80	0.04
3. Sorbitol 70%	20.0
4. Glycerol	10.0
5. Sucrose	30.0
6. Citric acid, monohydrate	0.1
7. Methyl-parahydroxybenzoate	0.07
8. Propyl-parahydroxybenzoate	0.03
9. Sodium chloride	0.04
10. Carboxymethyl cellulose	0.6
11 Silicon dioxide	2.0
12. Deionised water q.s.	ml 100

Preparation

[0023] The formulation is prepared (protecting from light) as follows:

1) a gel is prepared with deionised water and carboxymethyl cellulose (3.75% in water). The gel is left to swallow overnight.

2) a solution of water, sucrose (50%) and sodium chloride (0.5%) is prepared apart.

3) a mixture of nifuratel (0.4%) and Polysorbate 80 (1%) is prepared in water. The mixture is stirred until it becomes homogeneous.

4) In a closed vessel with a stirrer are added deionised water, sorbitol and glycerol, the solution 2) and sucrose. The mixture is maintained under continuous stirring. Then add methyl-parahydroxybenzoate, propyl-parahydroxybenzoate and silicon dioxide. Heat at 100 °C under stirring for 30 minutes. Cooling at 80°C citric acid is added. Then cooling at 40°C, add the gel 1) and the preparation 3) under continuous stirring.

[0024] The resulting syrup is a homogeneous suspension.

EXAMPLE 4

[0025] Oral gastro-resistant tablets, whose cores are produced as for example 2, are film-coated with a spray-suspension with the following quali-quantitative composition:

Ingredients
1. Methacrylic Acid Copolymer	10.0%
2. Triethyl Citrate	5.5%
3. Talc	4.5%
4. Titanium Dioxide	0.2%
5. 1N NaOH	5.5%
6. Water	74.3%

[0026] Procedure: add methacrylic acid copolymer slowly into 2/3 of the water and stir until the powder is completely wetted. Add, on sequence, the 1N NaOH solution and triethylcitrate into the polymer suspension and stir after each addition for about 60 minutes. In a separate vessel, homogenize talc and titanium dioxide in the remaining 1/3 of water for about 10 minutes and pour the obtained suspension into the polymer dispersion while stirring. Maintain the obtained spray-suspension on agitation. Transfer the tablets, prepared as for example 2, into a suitable equipped pan. Set temperature at about 40°C and start spraying with the previously obtained suspension, under moderate rotation speed. At the end of the coating process, start drying stirring and cool down at 25-30°C.

EXAMPLE 5

[0027] Oral gastro-resistant tablets, whose cores are produced as for example 2, are film-coated with a spray-suspension with the following quali-quantitative composition:

Ingredients
1. Cellulose Acetate Pthalate	12.0%
2. Diethyl Pthalate	4.0%
3. Peg-6000	1.5%
4. Water	82.5%

[0028] Procedure: add cellulose acetate pthalate into 1/3 of the water and stir until to obtain an homogeneous dispersion. Add diethyl pthalate and mix for about 30 minutes. In a separate vessel solubilize Peg-6000 in the remaining 2/3 of water and add the solution obtained to the cellulose pthalate dispersion. Mix for about 10 minutes. Proceed applying the coating to the tablets as for example 4 setting temperature at 70-80°C.

EXAMPLE 6

[0029] Oral gastro-resistant capsules, filled with the granules produced as for example 2 without the tabletting process, are film-coated with the spray-suspension described in example 4 or in example 5.

EXAMPLE 7

[0030] Oral gastro-resistant dragèes, whose cores are produced as for example 2, are film-coated with the spray-suspension described in example 4 or in example 5 and finally sugar coated with the following composition, using a proper coating pan:

1. Sucrose	54.00%
2. Corn Starch	3.50%
3. Titanium Dioxide	0.30%
4. Magnesium carbonate	11.00%
5. Gelatine	0.75%
6. Arabic Gum	0.75%
7. Wax	0.10%
8. Water	29.60%

Claims

1. Nifuratel or a physiologically acceptable salt thereof, for use in the treatment of any infection caused by one or more species of the genus Clostridium.

2. Nifuratel according to claim 1, characterized in that said species is selected from Clostridium difficile, Clostridium butyricum and Clostridium beijerinckii

3. Nifuratel according to claim Z, characterized in that said species is Clostridium difficile.

4. Nifuratel according to any of the preceding claims, characterized in that said infection is selected from intestinal tox-infections.

5. Nifuratel according to claim 4, characterized in that said intestinal tox-infection is Clostridium difficile associated diarrhoea.

6. Nifuratel according to any of the preceding claims, characterized in that it is administered in the form of a solid, semi solid or liquid pharmaceutical formulation.

7. Nifuratel according to claim 6, characterized in that said pharmaceutical formulation is selected from: tablets, film-coated tablets, capsules, dragées or syrup suitable for oral administration.

8. Nifuratel according to claims 6 or 7, characterized in that said formulation has a content in nifuratel or a salt thereof, from 10 to 1000 mg per single dose.

9. Nifuratel according to claims 6 or 7, characterized in that said formulation has a content in nifuratel or a salt thereof, from 50 to 800 mg per single dose.

10. Nifuratel according to claims 6 or 7, characterized in that said formulation has a content in nifuratel or a salt thereof, from 100 to 600 mg per single dose.

11. Nifuratel according to any of the preceding claims, characterized in that it is administered in combination or in temporal proximity with at least one active principle selected from antibiotics, probiotics, anti-diarrhoea agents.

12. Nifuratel according to claim 11, characterized in that said at least one antibiotic is selected from: metronidazole, vancomycin, bacitracine, rifaximine, aminoglycosides such as neomycin, gentamycin, amikacin, kanamycin and salts thereof.

13. Nifuratel according to claim 11, characterized in that said at least one antidiarrheal agent is selected from: bismuth subsalycilate, aluminium silicate, kaolin, activated charcoal, loperamide, attapulgite and zinc.

14. Nifuratel according to claim 11, characterized in that said at least one probiotic is selected from species of the genus Lactobacillus, Bacillus clausii and Saccharomyces bouillardii.